Microporous materials and multi-layer articles prepared therefrom

摘要

A microporous material is provided in the form of a singly extruded microporous sheet having opposing first and second surfaces, comprising: (a) a polymeric matrix component comprising: (i) 25 to 75 weight percent of low melt flow index polypropylene having a melt flow index ranging from 0.1 to 30 grams/10 minutes; (ii) 12.5 to 25 weight percent of ultrahigh molecular weight polyethylene; and (iii) 0 to 62.5 weight percent of high density polyethylene; (b) a finely divided, inorganic filler component dispersed throughout the polymeric matrix; and (c) a network of interconnecting pores communicating substantially throughout the microporous material, the pores constituting 10 to 80 percent by volume of the microporous material. The sheet typically has a thickness ranging from 3 to 8 mils and a stiffness of greater than 1 g/micron. In certain embodiments, the sheet has a density of greater than 0.75 g/cc. Also provided are multi-layer articles.